Recording Mixes

I have 2 x xdj 1000 mk2’s and a djm2000 nexus set up.
Can you tell me how to record onto my MacBook using rekordbox please?
I have the pro link all plugged in (I also have every other possible connection/leads/hubs if I need them, lan box, usb hub etc)
Using the memory stick and linking up and this works perfect for playback.
When I switch to the Macbook as the input, Rekordbox on the Mac operates really clunky and looks like it’s having trouble.
The record section is displayed but greyed out so you can’t click on the red record button?
Am I being a donut and doing something wrong?
Appreciate any advice
Chris